Photocell controlled shopping cart package detector

ABSTRACT

A system for detecting an article or the like on the lower storage section of a market cart as the cart passes through a scanning zone. The cart has a light reflective element mounted thereon operable to reflect a substantial portion of the light projected from a source back to said source. Sensing means are provided having a threshold level and operable to direct a beam of light to said reflective element and produce an output signal only when the intensity of light reflected back to the sensing means exceeds said threshold level. Scanning means are operable when conditioned by the output signal from said sensing means to scan the storage of the cart when it passes through the scanning zone. Signal means are operatively associated with said scanning means actuatable when said scanning means is conditioned and an article is present in the storage section of the cart.

United States Patent [191 Geisler Apr. 3, 1973 PHOTOCELL CONTROLLEDSHOPPING CART PACKAGE DETECTOR [76] Inventor: Edwin A. Geisler, 7339Central Avenue, Philadelphia, Pa. 191 ll [22] Filed: Sept. 27, 1971 [21]Appl. No.: 184,043

[52] US. Cl ..340/280 R, 340/258 B [51] Int. Cl. ..G08b 13/00 [58] Fieldof Search ..340/280 R, 258 B [56] References Cited UNITED STATES PATENTS3,157,871 11/1964 Umanoff ..340/280 Primary Examiner-Harold I. PittsAttorneyZachary T. Wobensmith [57] ABSTRACT A system for detecting anarticle or the like on the lower storage section of a market cart as thecart passes through a scanning zone. The cart has a light reflectiveelement mounted thereon operable to reflect a substantial portion of thelight projected from a source back to said source. Sensing means areprovided having a threshold level and operable to direct a beam of lightto said reflective element and produce an output signal only when theintensity of light reflected back to the sensing means exceeds saidthreshold level. Scanning means are operable when conditioned by theoutput signal from said sensing means to scan the storage of the cartwhen it passes through the scanning zone. Signal means are operativelyassociated with said scanning means actuatable when said scanning meansis conditioned and an article is present in the storage section of thecart.

7 Claims, 5 Drawing Figures PATENTEnAPRa 1915 5, 94

sum 1 [1F 2 PATENTEDAFRS ms SHEET 2 BF 2 Evin 96 -56 2E 93 XU WPHOTOCELL CONTROLLED SHOPPING CART PACKAGE DETECTOR BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates to adetecting system and more particularly to a system for detecting andsignalling the presence of articles on the lower shelf of a shoppingcart.

2. Description of the Prior Art The package detection system of thepresent invention has particular application in supermarkets of thelike. Shoppers in these markets usually employ a cart whichconventionally comprises a basket mounted on a frame in spaced relationto the lower frame section, thereby providing a shelf below the basketwhich shoppers often use for storage of items or articles selected fromthe store. As is conventional in most supermarkets, the checkout areaincludes a plurality of aisles through which the shopper and cart pass,and where the articles selected by the shopper are declared. Usuallythere is a counter adjacent the aisle on which the shopper places thearticles purchased, and the general arrangement is such that anyarticles on the lower shelf of the cart are not within easy view of thesupermarket checkout personnel. Thus, it has been found that there is asubstantial loss to the store by reason of the fact that the articlesstored on the lower shelf are often unwittingly or intentionally notdeclared by the shopper at the checkout area.

Various means have been employed to solve this problem, including theuse of mirrors mounted in the aisles to permit checkout personnel toview the lower shelf of carts. However, it has been demonstrated thatthese have not been satisfactory solutions. For example, checkoutpersonnel often do not employ the mirror to check out the bottom shelfof each cart as it passes through the station, particularly during busyrush hours. Additionally, in most instances the cart is only in theuseful range of the mirror during a brief period as it is moved throughthe checkout area. There is also the danger of accidental breakage ofglass mirrors.

There have been systems incorporating photoelectric detection means forthis purpose. However, these systems are generally much more complicatedand not as advantageous as the system of the present invention. A systemof this type is disclosed and claimed in Graveley, US. Pat. No.3,457,423, entitled Radiation Sensitive Detection System for ShoppingCarts. These prior systems have usually included a plurality ofphotoelectric detection devices and an alarm operatively associated withthe detectors, the alarm being operative any time all of the detectiondevices, except at least one discriminating beam are interceptedsimultaneously. The detection devices are selectively positioned at aplurality of vertically and laterally spaced locations in the aisle sothat all of the beams, except at least one, are intercepted by a carthaving a package on the lower shelf. This arrangement is designed todiscriminate between carts passing through the detection area which havea package on the lower shelf and carts which do not have a package onthe lower shelf. However, as a practical matter it has been found thatthe location of the package on the lower shelf of a cart may be suchthat it would intercept the discriminating beam and thus not actuate thealarm system. Further, it has been found that it is possible to actuatethe alarm by passage through the checkout aisle of something other thana cart with an object on its lower shelf and thus the system does nottruly discriminate in all practical cases.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a detection system which scans each cart as it passes throughthe checkout area and which gives a positive signal to the checkoutpersonnel of the presence of articles on the lower shelf in a mannerwhich is not embarrassing to the customer. To this end, the presentsystem utilizes a reflective element on the cart and there is providedat each checkout aisle a first sensor or sensing means adapted toproject a first light beam along a predetermined path to engage thereflector, which first beam when reflected is operative to condition ascanning circuit for scanning the lower shelf of each cart as it passesthrough the aisle. The scanning circuit includes a second sensor orsensing means projecting a second light beam disposed to be interceptedby an article on the lower shelf of the cart and, in this event, isoperable through a circuit to provide an output indication. Theindicator can be in the form of an alarm and/or a flashing lightdisposed adjacent the register and readily visible to the checkoutpersonnel. The reflecting element is preferably in the form of anelongated strip and the sensors are spaced laterally a predetermineddistance so that the scanning circuit is conditioned during the time thelower storage space of the cart is in the range of the lower sensor.Accordingly, by this system the scanning circuit is conditioned onlywhen a cart having the reflectihg element enters the scanning zone andif, for example, a customer or other object without a reflecting elementpasses through the zone, the scanning circuit is not conditioned andtherefore there is no signal emitted by such a passage through the zone.Accordingly, the system incorporates a discriminating feature and isoperative to be conditioned only by a shopping cart entering thescanning zone.

Another feature of the present invention is the use of a reflectingelement having retro-reflective" or "reflex-reflective capability; thatis, one wherein the reflecting surface has a predetermined highreflectance capacity and is operable to reflect a substantial portion ofthe light from a source back to the source in a wide angular incidencezone, that is the angular zone at which the light from the sourceengages the reflecting surface. Further, the threshold of the firstsensor permits an output signal to condition the scanning circuit onlywhen the reflected beam is within a given small angular receiving rangeof the sensor, and the light reflected is on an intensity exceeding thethreshold of the sensor; that is when the reflected beam is of apredetermined minimum intensity. This arrangement provides a furtherdiscriminating factor in the system. For example, it has been found thatother reflective elements havinga high reflectance and which effect amirror reflection would not be operative to trigger a conditioningsignal from the sensor since the reflected beam would fall outside theangular receiving range of the sensor, because the light beam emittedfrom the sensor would strike the reflecting element on the cart at aslight downward angle and therefore not return the beam to the sensor.Still other types of reflective elements, which effect diffusereflection of a beam, would also be inoperative in the present systemsince they effect diffusion of the reflected light with the result thatthe reflected portion returning along the transmitted path in thereceiving range of the sensor would not be powerful enough to produce asignal from the sensor to condition the scanning circuit. Accordingly,it is apparent that this provides a truly discriminating feature in thesystem of the present invention.

In the package detection system of the present invention, the secondsensor is preferably conditioned to scan the storage area of each cartduring the entire period the beam from the second sensor intercepts thestorage area. To this end, the retroreflective element preferably is inthe form of an elongated strip mounted on the frame of the cart and isof a predetermined length approximately equal to the length of thestorage space below the basket of the cart. Further, the sensors areselectively positioned in the aisle so that as the lead portion of theretro-reflective element is intercepted by the beam from the firstsensor, the beam from the second sensor traverses the lead portion ofthe storage area. Thus, the system will, as a practical matter, detectarticles in the storage area substantially irrespective of size orposition in the storage area.

The sensors are preferably located downstream of the portion of thecheckout area where the customer usually empties the contents of thecart and places articles on the counter so that when the cart passesthrough the scanning zone it is normally empty unless articles have beenleft on the lower shelf intentionally or unknowingly.

With the foregoing in mind, an object of the present invention is toprovide a system for detecting and signalling the presence of articleson' the lower shelf of a shopping market cart as it passes through, thecheckout area thereby to minimize the considerable financial lossoccasioned by the removal of articles from the store without having beendeclared.

Another object of the present invention is to provide a detection systemincluding discriminating means so that only carts with an object on thelower rack section actuate the signalling device.

These and other objects of the present invention and the variousfeatures from the description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The nature and characteristic featuresof the invention will be more readily understood from the followingdescription taken in connection with the accompanying drawings formingpart hereof, in which:

FIG. 1 is a plan view of a portion of a typical market checkout areaincorporating a detection and signalling system in accordance with thepresent invention;

FIG. 2 is an enlarged view of the shopping cart in the scanning zone asviewed on lines 2-2 of FIG. 1;

FIG. 3 is an enlarged view of the shopping cart at the scanning stationas viewed from line 3-3 of FIG. 1;.

FIG. 4 is a fragmentary schematic illustrating the path of a light beamreflected from a retro-reflecting element on the cast; and

FIG. 5 is a schematic wiring diagram of the detection and signallingsystem of the present invention.

Referring now to the drawings and particularly to FIG. 1 thereof, thereis illustrated a typical checkout area of a supermarket or the like. Thecheckout area comprises a plurality of side-by-side checkout counters 10where the items selected from the store are declared and paid for, thecounters 10 being spaced apart by aisles 12 through which the customersand carts C must pass. Each checkout counter 10 has a main counter area14 wherein the items purchased are placed, a recessed area 16 for thecashier, and a discharge area 18 where the checked out items are placedby the cashier prior to packaging in bags. These carts are ofconventional construction, and, as shown in FIG. 2, include a framestructure 20 having a lower rack section 21, a basket 24 supported onthe frame above the rack section 21 to provide a storage space 26between the rack section 21 and the bottom of the basket, and rollers 27depending from the frame to support the cart for movement along theground.

As noted above, it has been found that customers tend to use the storagespace 26 for larger items which they select in the store. As can be seenfrom FIGS. 1 and 3, items stored on the lower rack section 21 of thecart are not easily detectable by checkout personnel for the reason thatthe bottom of the basket shields the lower portion of the cart. Further,each aisle is only of a sufficient width to accommodate a cart and thewalls of the counter defining the aisle extend to the top of the cart.In accordance with the present invention, means is provided forsignalling the checkout personnel of the presence of items stored on thelower rack section 21 of the cart. To this end, in accordance with thepresent invention, there is provided a scanning zone or station Zsincluding a first sensor or sensing means S1 including means forprojecting a first light beam along a predetermined path and aphotoelectric detector for sensing light reflected from a reflectingelement E mounted on the cart C and which is operative to condition ascanning circuit Cs including a second sensor or sensing means S2 toscan the lower storage space 26 of the cart for the presence of objects.The second sensing means S2 also includes means for projecting a secondlight beam and a photoelectric detector for sensing reflected light. Thescanning circuit Cs includes means responsive to the sensors to providean audible and/or visual signal to the cashier in the event there is anobject present on the lower rack 21 of the cart as it passes through thescanning zone Zs.

In accordance with the present invention, the reflecting element E is inthe form of an elongated strip 29 mounted at a predetermined location onthe side of the cart C so that as the cart C passes through the scanningzone Zs, the light beam projected from the first sensing means S1 isintercepted by the strip. and the light is reflected to condition thescanning circuit Cs. In the system illustrated the strip 29 ispreferably disposed somewhat lower than the sensor S1 to minimize mirrorreflections.

An important feature of the systemof the present invention is theprovision of discriminating means in the system whereby an alarm signalis emitted only when a cart having an object in the storage space passesthrough the scanning zone. To this end, the photoelectric detector ofthe sensor S1 is preferably of the type having a predetermined limitedangular receiving area or zone and has a threshold level whereby itemits an output signal to condition the scanning circuit Cs only inresponse to a reflected beam of a predetermined minimum intensity in itsreceiving range or zone. Further, the reflecting strip 29 preferably isof the type having a reflecting face 31 exhibiting a high brilliancyreflex reflection of incident light, also referred to herein as havingretro-reflection capability. Accordingly, by this arrangement only areflected beam of a given minimum intensity reflected back to the sourceis operable to effect an output signal from the photoelectric detectorof sensor S1 to condition the scanning circuit Cs. A suitable reflectormaterial is one manufactured and sold under the tradename Scotchlite(No. 3870) by Minnesota Mining and Manufacturing Company, St. Paul,Minnesota, and disclosed and claimed in McKenzie US. Pat. No. 3,190,178,assigned to Minnesota Mining and Manufacturing Company. The reflectingsurface of this material has a high degree of reflectance and reflectssubstantially all light from a source back to the source over a largeangle of incidence, thereby insuring pickup of the reflected beam in asmall angular range of the sensor and substantially irrespective of theangular position of the cart as it is moved through the scanning zone.This feature minimizes the possibility of conditioning the scanningcircuit by reflecting means which either does not have a high enoughreflectance or does not reflect the beam within the angular receivingarea of the sensor, such as for example, the frame of the cart, yetassures conditioning when the cart if at various angles other thannormal to the incident beam.

Considering now the specific details of the circuitry of the detectingsystem and with reference to the schematic diagram of FIG. 5, there isprovided a main electrical supply source 30 having supply lines 32 and34. One terminal of the photocell of the first sensor S1 is connected tosupply line 34 through lead 38, and the other terminal to supply line 32by way of lead 40, the actuating coil 42 of normally-open relay 45, andlead 46. Switch arm 44 of relay 45, when closed, is connected throughlead 47 to control switch 58 of the scanning circuit Cs.

One terminal of the photocell of the second sensor S2 of the scanningcircuit Cs is connected through lead 52 to the supply line 34, and theother terminal is connected to supply line 32 through lead 54, actuatingcoil 56 of the relay 57, and lead 60. As illustrated, relay 57 isnormally energized to maintain its switch arm 58 in an open position.The other contact of relay 57 connects via lead 71 to relay coil 75 ofrelay 76 which has two ganged switch arms 77 and 79. Arm 77, whenclosed, connects supply line 32 to one terminal of visual signallingdevice 85 through lead 87, and to the upper end of relay coil 75 by wayof lead 91.

Arm 79 of relay 76, when closed, connects the supply line 34 to lead 81,variable resistor 82, and the lower terminal of audio signalling device83, the upper terminal of which is connected to supply line 32. Relaycoil 75 is also connected to the supply line 34 by lead 99, thermaldelay device 101 and switch 103.

Considering now the operation of the system, assume that a cart C with apurchased item P on its lower shelf 26 is passed through the checkoutarea into the scanning zone, to the position of the cart shown in FIG.

1. In this instance the first light beam of the upper sensor S1 isreflected from the reflecting element E on the cart and thereby throughphotocell of sensor S1 energizes relay 45 to close switch arm 44, whichconditions the scanning circuit Cs for operation. The package Pinterrupts the second light beam of the lower sensor S2, deenergizingrelay 57 and completing an energizing circuit via lead 71 to coil ofrelay 76. Energization of the coil 75 of the relay contact 76- closesswitches 77 and 79 to complete the circuit through lead 81 to theaudio-signalling device 83 and via lead 87 to the lightsignalling deviceon the cash register. Lead 91 then maintains the coil 75 of relay 76 inan energized condition. When a cart having an item P on its lower shelfis in the scanning zone and the audio signal 83 and signal light 85 areenergized in the manner set forth above, the duration of the audible andvisual alarms is limited by the thermal delay device 101. Morespecifically, after a predetermined time delay from closing of gangedswitch arms 77 and 79, for example five seconds, the normally closedswitch 103 opens as determined by the thermal delay device 99 therebyopening the circuit to the audio signal 83 and light signalling device85. After the cart C moves out of the scanning zone, relay 45 isdeenergized to open switch arm 44 and relay 57 is energized to openswitch 58, whereby coil 75 of relay 76 is deenergized to open switcharms 77 and 79 and in turn to open the circuit to the audible and visualsignalling devices 83 and 85. In the event the cart C with an item onits lower rack section remains in the scanning zone, the audible andvisual signalling devices repeat their signals at predetermined spacedintervals as determined by the thermal delay 101. Note that the scanningcircuit remains conditioned so long as the first light beam from thesensor S1 is reflected from the reflecting strip 29, and in order toscan the useful area of the storage space 26, the sensor S2 is locatedat a predetermined level H about the floor P so that the second lightbeam is projected above the lower frame section. Additionally, sensor S2is spaced laterally forward of sensor 81 so that as the lead portion ofreflective strip 29 comes into range of the first light beam from sensorS1, the second light beam from sensor S2 is directed across the leadportion of the storage space 26. Further, the strip 29 is of apredetermined length so that during the period the beam from sensor S2intercepts the depth of the storage space 26, the scanning circuit isconditioned.

On the other hand, assume that a cart C without an item P on its lowershelf passes through the checkout area into the scanning zone. In thisinstance the first light beam of the sensor S1 is reflected from thereflecting element E on the cart thereby again conditioning the scanningcircuit Cs by energizing relay 45 to close switch arm 44. However, inthis instance, since there is no package Pin the storage area 26 tointerrupt the second light beam from the lower sensor S2, the scanningcircuit is not conditioned for the reason that relay 56 remainsenergized to hold switch 58 open. This being the case, the armaturerelay 75 remains deenergized and the switch arms 77 and 79 remain open.Thus, the circuits to the audio signal and the signal light 85 are notcompleted and hence there is no audible or light signal.

One of the important features of the detection system of the presentinvention is the orientation of the scanning elements in the scanningzone and the particular circuit described above which effectivelydiscriminate and limit actuation of the audio signal and light signal tocarts having an item P on the lower shelf which, as noted above, wouldbe difficult for the personnel in the checkout areas to detect. This istrue for several reasons. First of all, with the particular type ofreflective element E described above, the scanning circuit isconditioned only when the reflective beam is of a given intensity and ina particular angular range of the sensor S1. In this regard it has beenfound that a shiny purse or even a coin would not be effective inconditioning the scanning circuit. Secondly, even if a reflectiveelement on an object other than a cart were to condition the scanningcircuit, the probability is that the reflective element of the objectwould pass out of the range of the beam of the sensor S1 when the objectpassed through the beam of the sensor S2 because of the orientation ofthe scanning zone.

I claim:

1. A system for detecting an article or the like on the lower storagesection of a market cart as the cart passes through a scanning zonewherein the cart having a light reflective element mounted thereon isoperable to reflect a substantial portion of the light projected from asource back to said source, comprising sensing means having a thresholdlevel and operable to direct'a beam of light to said reflective elementand produce an output signal only when the intensity of light reflectedback to the sensing means exceeds said threshold level,

scanning means operable when conditioned by the output signal from saidsensing means to scan the storage section of the cart when it passesthrough a scanning zone,

signal means operatively associated with said scanning means actuatablewhen said scanning means is conditioned and an article is present in thestorage section of the cart.

2. A system as claimed in claim 1 wherein said scanning means includes asecond means for projecting a second beam of light along a predeterminedpath to be intercepted by an article in the lower storage section.

3. A system for detecting an article or the like in the lower storagesection of a market cart, the cart having a retroreflective elementthereon capable of reflecting a wide incidence angle range a substantialportion of the light projected from a source back to the source,comprising a sensor having means for projecting a beam of light along apredetermined path and receiving means closely adjacent said projectedmeans and having a small angular receiving zone operable to produce anoutput signal when light from said projecting means is reflected fromsaid retro-reflective element,

scanning means operable when conditioned by the output signal from saidsensing means to scan the storage section of the cart when it passesthrough a scanning zone,

signal means operatively associated with said scanning means actuatablewhen said scanning means is conditioned and an article IS present in thestorage section of the cart.

4. A system for detecting an article or the like on the lower storagesection of a market cart, the cart having a light reflective elementmounted thereon, comprising means defining an aisle having a scanningzone through which the carts pass,

a first sensing means along said aisle including means for projecting afirst light beam across said aisle in a plane to be intercepted by thelight reflecting element on said cart, and

means producing an output signal,

a scanning circuit,

means operative to condition said scanning circuit when the first lightbeam from said first sensing means is reflected back to said firstsensing means,

said scanning circuit including a second sensing means including meansfor p ojecting a second light beam across said aisle alon apredetermined path to be intercepted by an a 'cle in the lower storagesection of the cart,

a signal me ns operable only when said scanning circuit is conditionedand said second light beam is intercepted by an article in the storagesection of the cart.

5. A system as claimed in claim 4 wherein said first sensing meansincludes a first light receiver adjacent said projecting means having athreshold operable to produce the output signal when the intensity ofthe reflected beam exceeds the threshold level of said first receiverand the reflective element has retro-reflective capabili ty operable ina predetermined wide range of incidence angle to reflect light from saidfirst projecting means to said first receiver.

6. A system as claimed in claim 4 wherein said reflective element is inthe form of a strip of a predetermined length located relative to thesensing means so that the scanning circuit is conditioned when thestorage section of the cart is in the range of said second light beam.

7. A system as claimed in claim 4 wherein said signal means comprisesaudio and visual indicators.

1. A system for detecting an article or the like on the lower storagesection of a market cart as the cart passes through a scanning zonewherein the cart having a light reflective element mounted thereon isoperable to reflect a substantial portion of the light projected from asource back to said source, comprising sensing means having a thresholdlevel and operable to direct a beam of light to said reflective elementand produce an output signal only when the intensity of light reflectedback to the sensing means exceeds said threshold level, scanning meansoperable when conditioned by the output signal from said sensing meansto scan the storage section of the cart when it passes through ascanning zone, signal means operatively associated with said scanningmeans actuatable when said scanning means is conditioned and an articleis present in the storage section of the cart.
 2. A system as claimed inclaim 1 wherein said scanning means includes a second means forprojecting a second beam of light along a predetermined path to beintercepted by an article in the lower storage section.
 3. A system fordetecting an article or the like in the lower storage section of amarket cart, the cart having a retroreflective element thereon capableof reflecting a wide incidence angle range a substantial portion of thelight projected from a source back to the source, comprising a sensorhaving means for projecting a beam of light along a predetermined pathand receiving means closely adjacent said projected means and having asmall angular receiving zone operable to produce an output signal whenlight from said projecting means is reflected from said retro-reflectiveelement, scanning means operable when conditioned by the output signalfrom said sensing means to scan the storage section of the cart when itpasses through a scanning zone, signal means operatively associated withsaid scanning means actuatable when said scanning means is conditionedand an article is present in the storage section of the cart.
 4. Asystem for detecting an article or the like on the lower storage sectionof a market cart, the cart having a light reflective element mountedthereon, comprising means defining an aisle having a scanning zonethrough which the carts pass, a first sensing means along said aisleincluding means for projecting a first light beam across said aisle in aplane to be intercepted by the light reflecting element on said cart,and means producing an output signal, a scanning circuit, meansoperative to condition said scanning circuit when the first light beamfrom said first sensing means is reflected back to said first sensingmeans, said scanning circuit including a second sensing means includingmeans for projecting a second light beam across said aisle along apredetermined path to be intercepted by an article in the lower storagesection of the cart, a signal means operable only when said scanningcircuit is conditioned and said second light beam is intercepted by anarticle in the storage section of the cart.
 5. A system as claimed inclaim 4 wherein said first sensing means includes a first light receiveradjacent said projecting means having a threshold operable to producethe output signal when the intensity of the reflected beam exceeds thethreshold level of said first receiver and the reflective element hasretro-reflective capability operable in a predetermined wide range ofincidence angle to reflect light from said first projecting means tosaid first receiver.
 6. A system as claimed in claim 4 wherein saidreflective element is in the form of a strip of a predetermined lengthlocated relative to the sensing means so that the scanning circuit isconditioned when the storage section of the cart is in the range of saidsecond light beam.
 7. A system as claimed in claim 4 wherein said signalmeans comprises audio and visual indicators.